(1/23) More on the largest ongoing environmental health crisis in the United States. Many of you asked for more details on our Tijuana River research after my thread yesterday []. Here's what we (@airborne_ucsd) have found so far — and why no one should be forced to breathe this toxic air for another day. 🧵

https://x.com/kprather88/status/2030399915940257851?s=20

(2/23) When ~240 million gallons of sewage recently leaked into the Potomac River near DC, it was declared a state of emergency within days. The @NYTimes incorrectly labelled it as the largest sewage leak in U.S. history. The Tijuana River releases that amount every few days continuously — and has for years. No emergency declaration. No national outcry. This is environmental injustice, plain and simple.

🧵Right now, 40–80 MILLION gallons of raw sewage and wastewater flow through San Diego's South Bay region EVERY DAY — poisoning the air, water, and people in some of California's most socio-economically challenged communities. This is the largest ongoing environmental crisis in the U.S. Most Americans have no idea. A thread. (1/10) 👇 My team's study in @ScienceMagazine (Rico et al., 2025) established for the first time a direct link between contaminated water and hazardous AIR quality. We measured hydrogen sulfide — a gas that attacks the respiratory and nervous systems — at 4,500x typical urban levels. (2/10)

1/ If I hear one more public official call indoor air filters a "band-aid," I'm going to explode! It's so logical, yet so readily dismissed. Filtering indoor air should be as standard as filtering water. Full stop. 🧵 2/ Measles, flu, COVID-19, norovirus—most infectious diseases spread through the air we breathe. We just accept that everyone gets sick indoors. It doesn't have to be this way.

The science/research landscape (at least in the US) has evolved so much since I began. It used to be about forming a hypothesis and exploring it—you might be right, you might be wrong. You'd design the best experiment to test it. Often in science, being "wrong" (1/) helps us end up learning so much more and possibly changing a longstanding "belief"-referred to as a paradigm shift. Now you get called out for being wrong and called all kinds of names by those (non-scientists) who your hypothesis/finding feel inconvenienced. (2/)

Getting questions about LA -- the air looks really clean right now. That is because the PM levels (which scatter light) are very low (the air is being pushed out to sea). However, air toxins are still present from the burning of structures and synthetic materials. More...(1/2) The AQ index being reported says "Good"--that is based on a handful of criteria pollutants like ozone and NOx (and PM). There are literally thousands of other gases present in the air right now which will react away and become more dilute over time. Stay safe. (2/2)

Sad to see a few surfers and couple of weak writers saying I was alarmist during Covid and now again w/ high H2S levels in air. Alarmist? Really? How about thank you for helping you and your family stay safe. Yes I still would not go in the ocean with raw sewage. Not a chance. Further..yes we have since shown that bacteria from the polluted ocean/river water can become airborne. No that dumb woman was not wrong then or now.

pubs.acs.org/doi/full/10.10…

In my 32 years, I have never been asked to share unpublished raw data before we publish it. We were concerned about the dangerously high levels of hydrogen sulfide, so we chose to share our validated preliminary results so SD county health could exercise the precautionary (1/) principle and immediately protect ALL people being exposed. All public health officials are supposed to do whatever it takes by any means necessary to protect public health once they are aware of potential high risk. The public has been sounding the alarm for years. (2/)

This is the "hot spot" we have identified in Imperial Beach where turbulence in the river releases extensive odor and river spray aerosols containing viruses, bacteria, and other pollutants. The foam extends from this point all the way to the ocean. Residents told me (1/2)





the area the "river" (better name is raw sewage discharge) runs thru "looks like a war zone". People who have lived here all their lives feel neglected. As they tell their stories they have tears in their eyes. Not one that I have met has not told horrific health stories (2/)

Today, @SupNoraVargas held an emergency press conference claiming the air in South Bay SD is safe. Yesterday, I presented our findings at a presser showing continuous, multi-day measurements of hydrogen sulfide (H2S) well above the CARB ambient hourly standard of 30 ppb (1/8) —indicating unsafe air quality. Vargas’s claim directly contradicts not only our calibrated, validated hydrogen sulfide (H2S) data but also the numerous health complaints from South Bay residents, including migraines, respiratory issues, and (2/8)

Getting ready to fly again. PSA: I will wear a mask the entire time in the airport & during boarding (highest risk times). Once we are at high altitude, I will assess the sounds of those around me. ACH are high so the key is to make sure those close to you are not sick. (1/3) If I feel "safe", I will remove my mask to eat/drink but I will keep it on the rest of the trip. So far, this has worked as I have not gotten COVID-19 yet even with travel. It is all a calculated risk and each person needs to decide knowing people are traveling while sick. (2/3)

I'm just re-read @WHO's recent report. As motivation, they state up front: ".....during the coronavirus disease (COVID-19) pandemic, the terms ‘airborne’, ‘airborne transmission’ and ‘aerosol transmission’ were used in different ways by stakeholders in different" (1/4) "scientific disciplines, which may have contributed to misleading information and confusion about how pathogens are transmitted in human populations."
My question which has not been addressed: (2/4)

Oh @WHO-adding more confusion, not less. Why remove "aerosols" which means those particles that remain suspended in air (vs droplets that drop quickly) and can become inhaled?? My head hurts after reading this convoluted mess. (1/2)

https://twitter.com/WHO/status/1780902039809130697

Question for @who and those who remained to help on this report (I stepped away after seeing the unhelpful path it was going)--do you really believe "infectious respiratory particle" clarifies the main pathway to infection for COVID-19 and other respiratory particles??? (2/2).

Trying to understand breakdowns in communication during the pandemic. We tried to write a publication with Saskia Popescu and Angie Rasmussen. They backed out when I refused to eliminate the word "airborne". Here are their exact words: "We believed that the goal of this" (1/) project was to harmonize terminology across disciplines so that future communications could be clear and unified. However, we disagree that the word “airborne” should be part of this consensus nomenclature. While the word “airborne” has a broad definition (2/)

Twitter was an incredible place to connect people globally to help get out the word on #COVIDIsAirborne. I met so many amazing people as a result. Great things happened based on these connections. My main goal has always been helping people understand how to....(1/10) protect themselves when public health failed by denying airborne transmission was occurring. As I said on 6/1/20 in my interview with @DrLaPook , this is a fixable problem IF we acknowledge SARS-CoV-2 is airborne. Why not? SARS-1 was airborne. Precautionary principle? (2/)

This is an example of where CONTEXT should never be ignored. Note that his email to Dr. Fauci has TWO parts: 1)"Is this news" regarding a recent article on the potential for airborne? & 2) What should we be telling people about visiting the hospital if they are feeling sick? (1/)

https://twitter.com/mdc_martinus/status/1714927088174551418

Note that his question "What is the right message?" is in the middle of his second message (the focus of briefing the next day)--not #1. The fact is @DrLaPook was the FIRST chief medical correspondent on a major TV network to go against what public officials were saying. (2/)

Email I just sent to @CDCgov director after seeing their abysmal report on masking...

Hello,

I have spent the last few years helping people understand how to protect against the airborne nature of SARS-2. The pandemic should and could have ended long ago.  (1/) Seeing CDC's latest article stating that surgical masks are as good as N95's (for an aerosol!) has made me question the motivation of CDC.  We drink 2L of water per day. We filter water to remove pathogens. We breathe 70,000 L of air per day--but we do not filter it. (2/)

Things are really not OK in the water or the air at Imperial Beach. State of emergency has been declared. Remember, you can pick the water you drink (or swim in) and the food you eat, but you cannot pick the air you breathe!



(1/4)nbcsandiego.com/news/local/san… This is a serious environmental issue that shows you cannot hide waterborne pollution. Let's not forget these waterborne pollutants and pathogens can become aerosolized (and airborne) in the Imperial Beach region which exposes many more people.

(2/4)

Today was the pinnacle in terms of witnessing the impact of COVID-19 denial for me. I sat in my student's exam and only 1 other person had a mask. People looked at me like I was crazy. The good news is that the ventilation was good based on CO2 levels when I walked in. (1/4)

https://twitter.com/kprather88/status/1668322718394253313

The bad news was when one of my colleagues got up and shut the door (see above). You can see the effect of what happened when they chose to do so. No one else seemed to care even though they were now in a petri dish of airborne pathogens. Massive shared air. (2/4)

My first year student Maile Heyer (co-advised with Lisa Zeigler) giving her first year seminar today @Scripps_Ocean. She talked about sampling the aerosolization of microbes from the ocean and potential health impacts. Feeling proud...it was an excellent presentation. @UCSanDiego Really important slide showing the motivation for her research...

Excellent article. Informative, clear, direct. One of the best of the pandemic.

Great job @jvipondmd @sameo416 @Mark_Ungrin -- thank you!! A few highlights below in thread (there are /many/ more in the article which is well worth a read)! (1/)

scientificamerican.com/article/masks-… .....they represent a well-understood engineered solution, with decades of widespread and successful use behind them. Demands to reject this evidence reflect a failure to recognize and respect interdisciplinary expertise that has undercut the global pandemic response. (2/)

.
.@theNASEM “Iceberg” provides the critical framework around which we reconcile our perceptions and understanding of #sexualharassment. The egregious cases make the news but we’re here to address that COMPLICIT OCEAN that keeps this ENTIRE ICEBERG afloat. See polls below (1/3). There are 14 examples of more hidden biases/harassments--how many have you experienced as a woman? (2/3)